Dietary intake in 6-year-old children from southern Poland: Part 2 – vitamin and mineral intakes

Studies on vitamin and mineral intakes in children are very important: Firstly because of the high prevalence of diet-related diseases and secondly because of the widespread consumption of highly processed foods which are characterised by high energy content and low density of essential nutrients.

R E S E A R C H A R T I C L E Open Access

Dietary intake in 6-year-old children from

intakes

Sylwia Merkiel*and Wojciech Chalcarz

Abstract

Background: Studies on vitamin and mineral intakes in children are very important: firstly because of the high prevalence of diet-related diseases and secondly because of the widespread consumption of highly processed foods which are characterised by high energy content and low density of essential nutrients Therefore, the purpose

of this study was to analyse vitamin and mineral intakes in 6-year-old children from southern Poland

Methods: Vitamin and mineral intakes were estimated from a three-day food record in 120 children, 64 girls and 56 boys, aged 6 years Nutrient densities were estimated as amounts per 1000 kcal (4185 kJ) of energy intake Statistical analysis was carried out by means of the IBM SPSS Statistics computer programme, version 19 The studied population was divided according to gender

Results: Intakes of folic acid (μg/1000 kcal) and vitamin C (mg, mg/1000 kcal) were significantly higher in girls Nutrient densities for all vitamins were higher in girls, however, these results did not reach statistical significance Intake of vitamin D was lower than EAR in all of the studied children Intakes of sodium (mg) and zinc (mg) were significantly higher in boys Intakes of the remaining minerals were higher in boys, however, these findings did not reach statistical significance Nutrient densities for all minerals, except for sodium, zinc and manganese, were higher in girls All of the studied children had sodium intakes above UL

Conclusions: Inadequate intakes of vitamin D, calcium and potassium in the studied 6-year-olds along with excessive sodium intake are the risk factors for developing osteoporosis and hypertension To prevent these diseases in the studied children, educational programmes for both preschool staff and parents should be worked out and implemented

Keywords: Children, Dietary intake, Vitamins, Minerals, Nutrition, Diet

Background

In recent years, children’s diets in the developed countries,

although high in energy, protein, fat and simple

carbohy-drates, are usually characterised by low vitamin and mineral

content Studies on school children showed that this is

largely due to an increased consumption of fast foods, salty

snacks, candy and soft drinks along with lower intakes of

fruit, vegetables, grains and milk [1] A study in

1.5-4.5-year-old children showed a decreasing intake of most

micronutri-ents with increasing intake of non-milk extrinsic sugars [2]

It was reported to be especially disturbing in the case of iron

and zinc which intakes fell below the Estimated Average Requirement in children who exceeded 24% of energy from non-milk extrinsic sugars [2] Another study in German 2-18-year-olds showed a strong inverse associ-ation between vitamin and mineral intakes and intake of added sugars [3] The authors [3] also reported that in-takes of the following food groups:‘meat, fish and eggs’,

‘fats and oils’, ‘grain’ and ‘fruits and vegetables’ fell with in-creasing intake of added sugars, with the strongest effect for‘fruits and vegetables’ In Norwegian children and ado-lescents, intakes of almost all micronutrients and intakes

of fruit and vegetables decreased with increasing content

of added sugar [4] Also in American preschoolers, intakes

of micronutrients, as well as grains, vegetables, fruits, and dairy decreased with increasing added sugar intake [5]

* Correspondence: sylwiamerkiel@awf.poznan.pl

Food and Nutrition Department of the Eugeniusz Piasecki University School

of Physical Education in Poznan, Poland Królowej Jadwigi 27/39 Street,

61-871 Poznan, Poland

© 2014 Merkiel and Chalcarz; licensee BioMed Central This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this

Merkiel and Chalcarz BMC Pediatrics (2014) 14:310

DOI 10.1186/s12887-014-0310-7

The observed trends are highly unfavourable, since

vita-mins and minerals are essential nutrients for healthy growth

and proper development of children Adequate intakes of

these micronutrients play also an important role in the

pre-vention of diet-related diseases Preventing these diseases

should start as early as in childhood [6] Since vitamins and

minerals are biologically active, both their deficiency and

ex-cess have unfavourable influence on human health,

espe-cially in childhood when providing adequate vitamin and

mineral intakes is crucial for the child’s physical, motor,

mental and emotional development It is particularly

import-ant for 6-year-old children who should attain school

readi-ness [6] because in Poland and some European countries

the age of six years is the last year of preschool attendance

[7] However, now in Poland, due to the changes in law,

more and more children start school at the age of six years,

similar to many European countries Therefore, adequate

in-takes of vitamins and minerals are indispensable for the

chil-dren to perform well at school The studies showed that

iodine, iron and folate are key nutrients for cognitive

devel-opment [8,9] and that other vitamins and minerals such as

vitamin B12or zinc may also be important [8]

After the year 2000, no publications on vitamin and

min-eral intakes of only 6-year-old children were found

How-ever, nine studies published in eleven articles [10-19]

reported intakes of selected micronutrients in populations

of wide age ranges including 6-year-olds All of these

stud-ies varied in terms of the age range of the studied children

and the number of vitamins and minerals which were

ana-lysed In the Polish national study on a representative

sam-ple [19] and in the British population study called the

National Diet and Nutrition Survey of young people aged

4–18 years [13], intakes of as many as eighteen

micronutri-ents in a subgroup of 4-6-year-old children were reported

Another British population study called the National Diet

2011/2012 [10] reported the intakes of even more

micronu-trients, nineteen, but in a subgroup of a wider age range,

that is from 4 to 10 years Intakes of eleven micronutrients

were presented for a representative sample of Belgian

pre-schoolers including a subgroup of 4–6.5-year-old children

[14] Intakes of vitamins and minerals in groups of children

of quite a narrow age ranges are available for Spanish

6-7-year-old children with intakes of nine micronutrients

re-ported [15,16] and for Cretan children aged 5.7-7.6 years

with intakes of thirteen micronutrients reported [18]

How-ever, in the latter study, intakes of vitamins and minerals

were expressed as nutrient density only Another study on

Spanish children reported intakes of sixteen micronutrients

in a subgroup of 6-9-year-old children [17] Even wider age

range was applied in the National Health and Nutrition

Examination Survey, 1999–2000, which reported intakes of

eighteen micronutrients in the United States population,

in-cluding a subgroup of 6-11-year-old children [11,12]

Taking into account the high prevalence of diet-related diseases and the widespread consumption of highly proc-essed foods which are characterised by high energy con-tent along with low density of essential nutrients, it is especially important to investigate vitamin and mineral in-takes in children Therefore, the purpose of this study was

to analyse vitamin and mineral intakes in 6-year-old chil-dren from southern Poland, including nutrient density Methods

Subjects

The studied population comprised 120 children, 64 girls and 56 boys, who attended the last grade in the preschools associated with the Nowy Sącz League of Preschools and Schools Promoting Health in Nowy Sącz and the vicinity The sampling design has been described in detail previ-ously [7] The study was approved by the Bioethics Com-mittee of the Poznan University of Medical Sciences

Vitamin and mineral intakes Data collection

To assess vitamin and mineral intakes in the studied chil-dren, parents and preschool staff were asked to keep a food record for three days: two preschool days and one free day (Sunday) Intakes of vitamin and mineral supplements were also taken into account All the details about the method were described in the previous part of this article [7]

Dietary assessment

Vitamin and mineral intakes were calculated using the Dieta 4.0 computer programme which contains food com-position database The programme estimates the changes

of nutritional value by calculating the losses of nutrients resulting from food processing This programme has been described in details in the previous articles [7,20]

Comparison with dietary reference intakes

Vitamin and mineral intakes of the studied 6-year-olds were compared to dietary reference intakes for Polish population [21] Intakes of vitamin A, B1, B2, B6, folic acid, vitamin B12, niacin, vitamin C, calcium, phosphorus, mag-nesium, iron, zinc, copper and iodine were compared to Estimated Average Requirement (EAR) [21] Intakes of vitamin E, sodium and potassium were compared to Adequate Intake (AI) [21] Dietary reference intakes for Polish population do not include EAR for vitamin D, thus intake of this vitamin was compared to EAR worked out

by the Food and Nutrition Board of the Institute of Medi-cine [22] Polish dietary reference intakes do not also in-clude manganese, therefore intake of this mineral was compared to AI worked out by the Food and Nutrition Board of the Institute of Medicine [23]

Moreover, vitamin and mineral intakes of the studied children were compared to Tolerable Upper Intake Level

(UL) when available Sodium intake was compared to

UL proposed by the National Food and Nutrition

Insti-tute in Warsaw [21] Intakes of retinol, vitamin D, E, B6,

folic acid, zinc, copper and iodine were compared to UL

worked out by the Scientific Committee on Food [24]

and intakes of niacin, vitamin C, calcium, phosphorus,

and Nutrition Board of the Institute of Medicine

[22,23,25-27] Magnesium intake was not compared to

UL This is because the UL was established for

magne-sium from nonfood sources and the studied children did

not take magnesium supplements Nutrient densities

were estimated as amounts per 1000 kcal (4185 kJ) of

energy intake

Statistical analysis

Statistical analysis was carried out by means of the IBM

SPSS Statistics computer programme, version 19 (Chicago,

IL, USA) The studied population was divided according to

gender Means, standard deviations (SD), medians and

standard errors (SE) were calculated for vitamin and

min-eral intakes The percentages of children with vitamin and

mineral intakes below EAR were calculated to investigate

the prevalence of inadequate intake In addition, the

per-centages of children with vitamin and mineral intakes above

UL were calculated to assess the risk of adverse health

ef-fects from excessive intake [28] The percentages of

chil-dren with nutrient intakes below AI were also presented,

similarly to previous studies [14], however, it should be

emphasised that AI cannot be used to estimate the

preva-lence of inadequate nutrient intakes for groups [28]

The same statistical methods as in the first part of the

art-icle were applied [7] In the case of the qualitative variables,

statistical significance was determined using Pearson’s

chi-square test For testing normality of the quantitative

vari-ables, the Shapiro-Wilk statistic was used For normally

dis-tributed variables, the unpaired Student’s t test was applied

to investigate statistically significant differences, whereas for

test was used The level of significance in the case of all the

tests was set atP ≤ 0.05

Results

Socio-demographic characteristics of the studied children

and their families were presented in the previous article

[7] Table 1 shows vitamin intakes in the studied

6-year-old children and Table 2 presents the percentages of the

studied 6-year-olds in the reference ranges for vitamin

in-takes Intakes of folic acid (μg/1000 kcal) and vitamin C

(mg, mg/1000 kcal) were significantly higher in girls It is

important to mention that nutrient densities for all

vita-mins were higher in girls, however, these results did not

reach statistical significance It is also noteworthy that

intake of vitamin D was lower than EAR in all of the stud-ied children

Table 3 presents mineral intakes in the studied 6-year-old children and Table 4 shows the percentages of the studied 6-year-olds in the reference ranges for mineral intakes Intakes of sodium (mg) and zinc (mg) were sig-nificantly higher in boys Also, intakes of the remaining minerals were higher in boys, however, these findings did not reach statistical significance Although statisti-cally insignificant, it is important to mention that nutri-ent densities for all minerals, except for sodium, zinc and manganese, were higher in girls Moreover, all of the studied children had sodium intakes above UL and sub-stantial percentage of them had intake of manganese above UL Substantial percentages of the studied 6-year-olds had intake of calcium below EAR and intake of po-tassium below AI

Discussion

Methodological remarks

To assess vitamin and mineral intakes in the studied 6-year-olds, we chose an estimated food record This method has the advantage of eliminating the problem of forgetting and improves estimation of portion size because the information is recorded at consumption [29] Since food record carries a higher respondent burden [29], we chose a three-day period Moreover, this method was most frequently used in the previous studies on vitamin and mineral intakes in children [14,18,30] The methods used

in other studies included a four-day estimated food record [10], a seven-day weighed food record [13], food fre-quency questionnaire [15,16], one 24-hour dietary recall [11,12,19] or a combination of 24-hour dietary recall and food frequency questionnaire [17] The differences in vita-min and vita-mineral intakes observed in the studied 6-year-olds and in the previously studied children [10-19] are surely caused by methodological differences However, most probably various food habits explain most of these differences For example, vitamin D intake was very low in all of the previously studied children [10,14,15,17,30] irre-spective of the method of dietary assessment and intake of vitamin A was much higher in Polish children, both in the studied 6-year-olds and in the previously studied 4-6-year-olds [19], in comparison to children from other countries, which may be explained by Polish food habits

Vitamin intakes

Mean intakes of all the analysed vitamins, except for vita-min D, were well above the reference values which implies low risk of inadequate intakes in the studied 6-year-old children It is particularly favourable in the case of vitamins B1, B2, B6, B12and folic acid This is because inadequate intakes of these vitamins are linked to elevated plasma homocysteine concentration which, in turn, is related to

Table 1 Vitamin intakes in the studied 6-year-old children

values

Girls (n = 64) Boys (n = 56) All children (n = 120) P Girls (n = 64) Boys (n = 56) All children (n = 120)

Vitamin A (retinol equivalent)

Retinol

Beta-carotene

Vitamin D

Vitamin E

Vitamin B1

(mg/1000 kcal) NA 0.565 0.177 0.536 0.198 0.551 0.187 0.352 0.524 0.022 0.492 0.027 0.513 0.017

Vitamin B2

(mg/1000 kcal) NA 0.958 0.258 0.880 0.247 0.922 0.255 0.071 0.937 0.032 0.865 0.033 0.910 0.023

Vitamin B6

Folic acid

Vitamin B12

Table 1 Vitamin intakes in the studied 6-year-old children (Continued)

Niacin

Vitamin C

NA – not available; P – significance.

1

EAR; 2

AI.

increased risk of cardiovascular diseases, such as coronary

heart disease and stroke [31,32] This is of great importance

to the studied children because of their excessive intake of

saturated fatty acids and animal protein along with

inad-equate intake of polyunsaturated fatty acids, which pose the

risk of developing cardiovascular diseases, as reported in the

previous article [7] Therefore, inadequate intakes of B

vita-mins would aggravate the risk of developing these diseases

in the studied 6-year-olds Additionally, the same effect

would have inadequate intakes of antioxidant vitamins and

so it is highly favourable that intakes ofβ-carotene and

vita-mins E and C pose low risk of inadequate intake in the

stud-ied children

The only major concern in the studied 6-year-olds is low

intake of vitamin D which implies high risk of inadequate

intake Similar or even lower intakes of vitamin D were

observed in 4-10-year-old [10] and 7-year-old [30] British children, and in Spanish 6-9-year-old children [17] Also, Belgian 4–6.5-year-olds [14] were characterised by lower intake of vitamin D compared to the studied 6-year-olds and almost all of them had intakes lower than Belgian rec-ommendations Such low intake of vitamin D is highly dis-concerting because it may adversely affect the studied children’s bones and teeth [33,34] Moreover, studies imply that deficiency of this vitamin has negative impact on insu-lin resistance andβ cell function [35-37] increasing the risk

of diabetes Although vitamin D is synthesised as a result of exposure to solar ultraviolet-B irradiation [38], in Polish cli-matic conditions such low intake of vitamin D is unlikely to

be compensated by cutaneous synthesis of this vitamin It is highly surprising that the staff of preschools promoting health failed to spread the recommendation of eating fish

Table 2 The percentages of the studied 6-year-old children in the reference ranges for vitamin intakes

Nutrient

Girls (n = 64)

Boys (n = 56)

All children

Vitamin A (retinol equivalent)

Retinol

Vitamin D

Vitamin E

Vitamin B 1

Vitamin B 2

Vitamin B 6

Folic acid

Vitamin B 12

Niacin

Vitamin C

P – significance;

# – P cannot be calculated when percentage is 0.0 or 100.0.

frequently which would prevent inadequate vitamin D

in-takes in the studied children

In the previous studies on vitamin intakes, 6-year-old

children were included in groups of children of various age

ranges [10-19], therefore, direct comparison to other

stud-ies is not possible Only nutrient density may be compared

directly because it is not dependent on total energy intake

In Cretan 5.7-7.6-year-old children [18] nutrient densities

were higher than in the studied 6-year-olds for six out of

nine analysed vitamins, that is for vitamin B1, B2, B6, folic

acid, niacin and vitamin C [18] Serra-Majem et al [17] and

Glynn et al [30] also analysed nutrient densities but in the

former study the amounts of vitamins were given per

1000 kJ of energy intake while in the latter study only statis-tically significant differences according to gender were ana-lysed and no values were presented

Although vitamin intakes cannot be compared directly to other studies, it is interesting to note that intake of vitamin

A in the studied 6-year-old children was much higher than

in British 4-6-year-olds [13], but also much higher than in older groups of children: 4-10-year-old [10] and 7-year-old [30] British children, 6-7-year-old [15,16] and 6-9-year-old [17] Spanish children, and even in the United States 6-11-year-olds [12] In Polish 4-6-6-11-year-olds [19], intake of vitamin

Table 3 Mineral intakes in the studied 6-year-old children

Nutrient Referencevalues

Girls (n = 64)

Boys (n = 56)

All children (n = 120) P

Girls (n = 64)

Boys (n = 56)

All children (n = 120)

Calcium

Phosphorus

Magnesium

Sodium

Potassium

Iron

Zinc

Copper

(mg) 0.31 0.88 0.18 0.93 0.19 0.90 0.19 0.134 0.86 0.02 0.91 0.03 0.87 0.02 (mg/1000 kcal) NA 0.50 0.08 0.49 0.08 0.49 0.08 0.704 0.49 0.01 0.48 0.01 0.49 0.01 Manganese

(mg) 1.52 3.00 0.79 3.23 0.77 3.11 0.79 0.106 2.90 0.10 3.17 0.10 3.09 0.07 (mg/1000 kcal) NA 1.70 0.41 1.71 0.38 1.70 0.40 0.829 1.69 0.05 1.62 0.05 1.66 0.04 Iodine

( μg) 651 129.3 31.9 138.4 35.7 133.5 33.9 0.144 130.5 4.0 136.0 4.8 132.3 3.1 ( μg/1000 kcal) NA 73.8 19.6 73.4 18.4 73.6 19.0 0.925 71.5 2.4 72.2 2.5 71.7 1.7

NA – not available; P – significance.

1

EAR; 2

AI.

A was also lower in comparison to the studied 6-year-old

children, but it was higher than in children from other

countries irrespective of age In comparison to those studies

in which intakes of retinol [10,13,19,30] and β-carotene

[13,19,30] were analysed, intakes of these nutrients were also

the highest in the studied children as well as in the

previ-ously studied Polish 4-6-year-olds [19] This high intake of

vitamin A in the studied 6-year-old children may be

ex-plained by high consumption of carrot juice which is very

popular in Poland, especially among children and

adoles-cents There are many brands of carrot juice in Poland

ad-dressed particularly to the youngest consumers Moreover,

the studied children attended preschools promoting health

where the staff tried to implement the habit of eating

vegeta-bles The region where the studied children lived is not

afflu-ent and carrot which is not an expensive vegetable was

often consumed by the children at preschool The other

habit which surely increased vitamin A intake is daily use of

butter which is in Poland the most popular fat to spread on

sandwiches

In the previous studies, which reported vitamin intakes

in children of similar age to the studied 6-year-olds, the

populations of children were divided according to gender

[10,12-14,17-19,30], except for the Spanish 6-7-year-olds

[15,16] whose intakes were analysed according to the city

where the children lived However, statistically significant

differences according to gender were tested only in two of

those studies [14,30]

It was expected to find many statistically significant

differ-ences in vitamin intakes between the studied girls and boys

However, it turned out not to be true in the studied

chil-dren Glynn et al [30] found statistically significant

differ-ences in intakes of five vitamins in English 7-year-olds, while

Huybrechts and De Henauw [14] found significant

differ-ences in intakes of four vitamins in Belgian 4–6.5-year-olds

In the previous studies, vitamin intakes were usually

reported to be higher in boys than in girls [10,12-14,17]

Only in 7-year-old English children [30], girls were

β-carotene, and in 4-6-year-old Polish children [19] girls

β-carotene, vitamin B2, niacin and vitamin C However,

these differences were minor and statistically

insignifi-cant Quite opposite, Huybrechts and De Henauw [14]

found statistically significantly lower intakes of vitamins

com-parison to their male peers, while Glynn et al [30] in the

group of English 7-year-olds found statistically

signifi-cantly lower intakes of vitamins B1, B2, B6, niacin and

folic acid in females in comparison to males

Among the previous studies on vitamin intakes in

chil-dren of similar age to the studied 6-year-olds, nutrient

densities for vitamins were analysed only in three of them

[17,18,30] Unlike in the studied 6-year-olds, nutrient

densities for vitamins were not always higher in girls Glynn et al [30] found higher nutrient densities in English 7-year-old girls only for vitamin A, retinol andβ-carotene, however, all these differences were statistically significant Smpokos et al [18] reported higher nutrient densities in Cretan 5.7-7.6-year-old girls for as many as six out of nine analysed vitamins but Serra-Majem et al [17] reported higher nutrient densities in 6-9-year-old Spanish girls for only three out of ten vitamins However, neither Smpokos

et al [18] nor Serra-Majem et al [17] tested statistically significant differences according to gender

Mineral intakes

It is surprising that the studied 6-year-old children are at risk of inadequate calcium intake The importance of drinking milk to children’s bone health has been spread throughout the Polish society for many years and even television has broadcast a series of spots promoting the habit of daily milk drinking Also, the producers of dairy products use this recommendation in the commercials Moreover, the children attended preschools promoting health and therefore it would seem obvious that basic nu-tritional guidelines should be promoted by the preschool staff Most of the preschool staff and the studied children’s parents knew that high intake of milk and dairy products

in childhood prevents osteoporosis [39,40] and that milk and dairy products are rich sources of calcium [41,42] The adverse effect of inadequate calcium intake may be aggravated by the abovementioned inadequate vitamin D intake and by quite high phosphorus intake Although the studied children did not exceed the UL, phosphorus in-take was much higher than calcium inin-take This may dis-turb the proportion of calcium to phosphorus which should be about 1.2 : 1 in children’s diet according to the Polish recommendations [43]

Another adverse characteristic of the studied 6-year-olds’ diets was excessive intake of sodium found in all of the studied children Exceeding sodium UL poses the risk of developing hypertension, particularly when taking into account quite low potassium intake Although EAR for potassium has not been established, mean intake below AI shows the need to increase intake of this min-eral to prevent hypertension in the studied 6-year-olds

It is unexpected that the preschool staff failed to con-vince the parents of the necessity to reduce salt intake and did not implement this simple rule during the prep-aration of preschool meals It is even more surprising when taking into account that the majority of both the preschool staff and the studied children’s parents knew that high salt intake increases the risk of hypertension [39,40] These findings confirm the necessity to imple-ment programme aimed at reducing salt intake as pro-posed in the previous article [44]

It is also disconcerting that manganese intake exceeded

UL in about a half of the studied children However,

bio-availability of this mineral from food sources have been

found to be affected by other dietary factors [23], such as

phytate which reduces the efficiency of absorption of

man-ganese [45] Therefore, blood manman-ganese concentration

should be measured in the studied children to conclude

whether manganese intake is excessive

Similarly to vitamin intakes, also mineral intakes cannot

be compared directly to the results of other studies because

of the age differences among the studied populations of

children However, it is important to note that sodium

in-take in the studied children was higher than in 4-6-year-old

Polish children [19] and much higher than in 4-6-year-old

British children [13] and 4–6.5-year-old Belgian children

[14] Moreover, it was higher even than in older children: British 7-year-olds [30], as well as 6-7-year-old [15,16] and 6-9-year-old [17] Spanish children Nutrient densities for calcium, potassium and iron in the studied children were lower than nutrient densities for these minerals in Cretan 5.7-7.6-year-olds [18] However, nutrient density for sodium

in the studied 6-year-olds was much higher than in Cretan 5.7-7.6-year-olds [18] Nutrient densities for other minerals were not analysed by Smpokos et al [18]

Contrary to expectations and similarly to vitamin in-takes, there were statistically significant gender differences

in the intakes of only two minerals in the studied 6-year-olds Among those studies in which differences in mineral intakes were tested according to gender, only two of them reported statistically significant differences [14,30]

Table 4 The percentages of the studied 6-year-old children in the reference ranges for mineral intakes

Nutrient

Girls (n = 64)

Boys (n = 56)

All children

Calcium

Phosphorus

Magnesium

Sodium

Potassium

Iron

Zinc

Copper

Manganese

Iodine

P – significance;

# – P cannot be calculated when percentage is 0.0 or 100.0.

Higher intakes of all the analysed minerals in the

studied 6-year-old boys compared to their female peers,

were also observed in all of the previously studied

chil-dren [10,11,13,14,17,19,30] Only calcium intake in

Polish 4-6-year-old boys [19] and magnesium intake in

4–6.5-year-old Belgian boys [14] were not higher than

in their female peers Moreover, Huybrechts and De

Henauw [14] and Glynn et al [30] reported these

differ-ences to be statistically significant, except for selenium

intake in 7-year-old English boys [30]

Higher nutrient densities for most of the analysed

min-erals in the studied 6-year-old girls compared to their male

peers were not as noticeable as in the case of vitamins

Smpokos et al [18] reported higher nutrient densities for

three out of four minerals in Cretan 5.7-7.6-year-old girls

but Serra-Majem et al [17]– only for two out of six

min-erals in Spanish 6-9-year-old girls

Conclusions

In conclusion, inadequate intakes of vitamin D, calcium

and potassium in the studied 6-year-olds along with

ex-cessive sodium intake are the risk factors for developing

osteoporosis and hypertension To prevent these diseases

in the studied children, educational programmes for both

preschool staff and parents should be worked out and

implemented

Competing interests

The authors declare that they have no competing interests.

Authors ’ contributions

SM and WC conceptualized and designed the study SM searched for the

literature, extracted and analysed data, and drafted the initial manuscript WC

analysed data and critically reviewed the initial manuscript SM and WC

approved the final manuscript as submitted.

Acknowledgements

Financial support was received from the Polish Ministry of Science and

Higher Education.

Received: 8 September 2014 Accepted: 8 December 2014

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